Linked by Thom Holwerda on Sat 6th Oct 2012 13:59 UTC, submitted by robojerk
Linux "F2FS is a new file system carefully designed for the NAND flash memory-based storage devices. We chose a log structure file system approach, but we tried to adapt it to the new form of storage. Also we remedy some known issues of the very old log structured file system, such as snowball effect of wandering tree and high cleaning overhead."
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Jaegeuk Kim - lots of maybe
by WereCatf on Mon 8th Oct 2012 21:34 UTC
Member since:
2006-02-15 :

After forum, I can share the slides, and I hope they will be useful to you.

Instead, let me summarize at a glance compared with other file systems.
Here are several log-structured file systems.
Note that, F2FS operates on top of block device with consideration on the FTL behavior.
So, JFFS2, YAFFS2, and UBIFS are out-of scope, since they are designed for raw NAND flash.
LogFS is initially designed for raw NAND flash, but expanded to block device.
But, I don't know whether it is stable or not.
NILFS2 is one of major log-structured file systems, which supports multiple snap-shots.
IMO, that feature is quite promising and important to users, but it may degrade the performance.
There is a trade-off between functionalities and performance.
F2FS chose high performance without any further fancy functionalities.

Maybe or obviously it is possible to optimize ext4 or btrfs to flash storages.
IMHO, however, they are originally designed for HDDs, so that it may or may not suffer from fundamental designs.
I don't know, but why not designing a new file system for flash storages as a counterpart?

I somehow get the feeling that they didn't actually do much research on the existing filesystems and just decided to write one from the scratch. I mean, there's a lot of "if" and "maybe" there and no actual reasoning whatsoever. I am quite certain that e.g. ext4 could be a viable flash-filesystem with some changes and since it's an already proven and tested filesystem it's much less likely to contain any bad bugs. Also, Jaegeuk mentions they're not including any advanced functionality, only the basics, and thus I cannot help but wonder if writing patches for an existing FS would have been better use of everyone's time.

EDIT: Forgot to add the link.

Edited 2012-10-08 21:34 UTC

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